#include <cstdio>
#include <iostream>
using namespace std;

long long a[200000]={0};

long long abslong(long long a)
{
	if (a<0)
		return(-a);
	else
		return(a);
}

int main(void)
{
	freopen("dec.in","r",stdin);
	freopen("dec.out","w",stdout);
	int i,j,n;
	long long c,total=0;
	cin>>n>>c;
	for (i=0;i<n;i++)
		cin>>a[i];
	for (i=0;i<n;i++)
		for (j=i+1;j<n;j++)
			if (abslong(a[i]-a[j])==c)
				total++;
	cout<<total<<endl;
	fclose(stdin);
	fclose(stdout);
	return(0);
}